This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The nuclear pore complex (NPC) is a large macromolecular structure composed of at least 30 different protein subunits. The most obvious roles of the NPC is being the sole gateway for nucleocytoplasmic exchange of macromolecules, either through passive diffusion or facilitated transported. The NPC consists of three distinct architectural structures: the central framework, the cytoplasmic filaments and the nuclear basket. The central framework is believed to form the channel that connects the cytoplasm and inner nucleus. The NPC contains an eight fold symmetry. Due do this symmetry, most nucleoporin should be present at a copy number of eight or a multiple of eight. Most of the nucleoporins are located symmetrically on both sides of the NPC, whereas only a few are positioned at either the nuclear or the cytoplasmic face. For a complete picture of the NPC architecture a high resolution three dimensional structure would be required. However, it is not feasible to obtain such a map on the complete structure at once. A collaborative approach taken by the Blobel lab to build such a model is underway. I have cocystalized two components of the nuclearpore complex, Sec13 and a fragment of Nup96.